Translation

(itstool) path: legalnotice/para
3Com and HomeConnect are registered trademarks of 3Com Corporation.
67/670
Context English Portuguese (Brazil) State
_ translator-credits Edson Brandi, ebrandi@FreeBSD.org, 2018
Danilo G. Baio, dbaio@FreeBSD.org, 2018
Filtering Bridges Pontes de Filtragem (Filtering Bridges)
<email>ale@FreeBSD.org</email> <email>ale@FreeBSD.org</email>
<personname><firstname>Alex</firstname><surname>Dupre</surname></personname><affiliation> <_:address-1/> </affiliation> <personname><firstname>Alex</firstname><surname>Dupre</surname></personname><affiliation> <_:address-1/> </affiliation>
FreeBSD is a registered trademark of the FreeBSD Foundation. FreeBSD is a registered trademark of the FreeBSD Foundation.
3Com and HomeConnect are registered trademarks of 3Com Corporation. 3Com and HomeConnect are registered trademarks of 3Com Corporation.
Intel, Celeron, Centrino, Core, EtherExpress, i386, i486, Itanium, Pentium, and Xeon are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States and other countries. Intel, Celeron, Centrino, Core, EtherExpress, i386, i486, Itanium, Pentium, and Xeon are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States and other countries.
Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this document, and the FreeBSD Project was aware of the trademark claim, the designations have been followed by the <quote>™</quote> or the <quote>®</quote> symbol. Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this document, and the FreeBSD Project was aware of the trademark claim, the designations have been followed by the <quote>™</quote> or the <quote>®</quote> symbol.
$FreeBSD: head/en_US.ISO8859-1/articles/filtering-bridges/article.xml 53717 2019-12-29 14:13:50Z carlavilla $ $FreeBSD: head/en_US.ISO8859-1/articles/filtering-bridges/article.xml 53717 2019-12-29 14:13:50Z carlavilla $
Often it is useful to divide one physical network (like an Ethernet) into two separate segments without having to create subnets, and use a router to link them together. The device that connects the two networks in this way is called a bridge. A FreeBSD system with two network interfaces is enough in order to act as a bridge. Geralmente, é útil dividir uma rede física (como uma Ethernet) em dois segmentos separados, sem precisar criar sub-redes, e usar um roteador para vinculá-los. O dispositivo que conecta as duas redes dessa maneira é chamado de ponte (bridge). Um sistema FreeBSD com duas interfaces de rede é suficiente para atuar como uma ponte.
A bridge works by scanning the addresses of <acronym>MAC</acronym> level (Ethernet addresses) of the devices connected to each of its network interfaces and then forwarding the traffic between the two networks only if the source and the destination are on different segments. Under many points of view a bridge is similar to an Ethernet switch with only two ports. Uma ponte funciona examinando os endereços do nível <acronym>MAC</acronym> (endereços Ethernet) dos dispositivos conectados a cada uma de suas interfaces de rede e encaminhando o tráfego entre as duas redes apenas se a origem e o destino estiverem em diferentes segmentos. Sob muitos pontos de vista, uma ponte é semelhante a um switch Ethernet com apenas duas portas.
Why use a filtering bridge? Por que usar uma ponte de filtragem?
More and more frequently, thanks to the lowering costs of broad band Internet connections (xDSL) and also because of the reduction of available IPv4 addresses, many companies are connected to the Internet 24 hours on 24 and with few (sometimes not even a power of 2) IP addresses. In these situations it is often desirable to have a firewall that filters incoming and outgoing traffic from and towards Internet, but a packet filtering solution based on router may not be applicable, either due to subnetting issues, the router is owned by the connectivity supplier (<acronym>ISP</acronym>), or because it does not support such functionalities. In these scenarios the use of a filtering bridge is highly advised. Cada vez mais frequentemente, graças aos custos reduzidos de conexões de banda larga à Internet (xDSL) e também devido à redução de endereços IPv4 disponíveis, muitas empresas estão conectadas à Internet 24 horas por dia e com poucos (às vezes nem mesmo 2) endereços IP. Nestas situações, geralmente é desejável ter um firewall que filtre o tráfego de entrada e de saída de e para a Internet, mas uma solução de filtragem de pacotes baseada em roteador pode não ser aplicável, quer seja devido a problemas de sub-redes, quer seja porque o roteador é de propriedade do provedor de conectividade (<acronym>ISP</acronym>), ou porque ele não suporta tais funcionalidades. Nestes cenários, o uso de uma ponte de filtragem é altamente recomendado.
A bridge-based firewall can be configured and inserted between the xDSL router and your Ethernet hub/switch without any IP numbering issues. Um firewall baseado em uma ponte de filtragem pode ser configurado e inserido entre o roteador xDSL e seu hub/switch Ethernet sem causar nenhum problema de numeração IP.
How to Install Como instalar
Adding bridge functionalities to a FreeBSD system is not difficult. Since 4.5 release it is possible to load such functionalities as modules instead of having to rebuild the kernel, simplifying the procedure a great deal. In the following subsections I will explain both installation ways. Adicionar funcionalidades de bridge a um sistema FreeBSD não é difícil. Desde a versão 4.5 é possível carregar tais funcionalidades como módulos ao invés de ter que reconstruir o kernel, simplificando bastante o procedimento. Nas subseções seguintes, explicarei as duas formas de instalação.
<emphasis>Do not</emphasis> follow both instructions: a procedure <emphasis>excludes</emphasis> the other one. Select the best choice according to your needs and abilities. <emphasis>Não</emphasis> siga as duas instruções: um procedimento <emphasis>exclui</emphasis> o outro. Selecione a melhor opção de acordo com suas necessidades e habilidades.
Before going on, be sure to have at least two Ethernet cards that support the promiscuous mode for both reception and transmission, since they must be able to send Ethernet packets with any address, not just their own. Moreover, to have a good throughput, the cards should be PCI bus mastering cards. The best choices are still the Intel <trademark>EtherExpress</trademark> Pro, followed by the <trademark class="registered">3Com</trademark> 3c9xx series. To simplify the firewall configuration it may be useful to have two cards of different manufacturers (using different drivers) in order to distinguish clearly which interface is connected to the router and which to the inner network. Antes de continuar, certifique-se de ter pelo menos duas placas Ethernet compatíveis com o modo promíscuo para recepção e transmissão, pois elas devem ser capazes de enviar pacotes Ethernet com qualquer endereço, não apenas o deles. Além disso, para ter uma boa taxa de transferência, as placas devem ser placas do barramento PCI. As melhores opções ainda são as Intel <trademark>EtherExpress</trademark> Pro, seguido pela série <trademark class="registered">3Com</trademark> 3c9xx. Para simplificar a configuração do firewall, pode ser útil ter duas placas de diferentes fabricantes (usando drivers diferentes) para distinguir claramente qual interface está conectada ao roteador e qual está conectada à rede interna.
Kernel Configuration Configuração do Kernel
So you have decided to use the older but well tested installation method. To begin, you have to add the following rows to your kernel configuration file: Então você decidiu usar o método de instalação mais antigo, e também o mais bem testado. Para começar, você precisa adicionar as seguintes linhas ao seu arquivo de configuração do kernel:
options BRIDGE
options IPFIREWALL
options IPFIREWALL_VERBOSE
options BRIDGE
options IPFIREWALL
options IPFIREWALL_VERBOSE
ComponentTranslation
This translation Translated FreeBSD Doc/articles_filtering-bridge 3Com and HomeConnect are registered trademarks of 3Com Corporation.
The following string has the same context and source.
Translated FreeBSD Doc/books_handbook 3Com and HomeConnect are registered trademarks of 3Com Corporation.

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Glossary

English Portuguese (Brazil)
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Source information

Source string comment
(itstool) path: legalnotice/para
Flags
ignore-same
Source string location
article.translate.xml:16
String age
a year ago
Source string age
a year ago
Translation file
articles/pt_BR/filtering-bridges.po, string 6